An inkjet recording method is a recording method for forming an image by providing small ink droplets to a recording medium such as plain paper and a glossy medium, and has become rapidly widespread due to price reduction and improvement of recording speed. Further, in addition to that high-definition of an image obtained by the inkjet recording method is advanced, and along with rapid spread of digital cameras, the method has become widely common as an output method of images comparable to a silver halide photograph.
Examples of the problem of the ink jet recording method include deterioration in image fastness of the recorded material obtained. In general, the recorded matter obtained by the inkjet recording method has low image fastness as compared to a silver halide photograph. Specifically, when the recorded material is exposed to water, light, humidity, heat, environmental gases present in the air or the like for a long period of time, there is a problem in that a color material on the recorded material is likely to deteriorate, which causes a change in color tone or color fading of the image.
In forming a color image, an ink set in which ink compositions with a plurality of colors are combined with each other is used. In the ink set, when image fastness such as light resistance or ozone resistance of a specific ink composition are significantly lower than those of the other ink compositions, a color formed by the specific ink composition is faded or discolored more rapidly than the other colors, and thus the color tone balance of the entire color image deteriorates. Therefore, it is preferred that the image fastness of each ink composition constituting the ink set is excellent and a difference in image fastness between the respective ink compositions is small.
Among yellow, magenta and cyan inks widely used as ink for inkjet, magenta, in particular, light resistance of the image of yellow ink tends to be inferior to that of images of the other inks. As a colorant used in the yellow ink, various azo compounds are known (for example, Patent Documents 1 to 8).
With respect to such problems, various yellow inks color tones of which are good and which are aimed to improve fastness to light, moist heat and gas such as ozone have been proposed (see Patent Documents 9 to 11).
Further, Patent Document 12 discloses an ink composition containing at least two or more yellow dyes which satisfy a relationship of a specific wavelength.
Further, in the ink for inkjet, from the viewpoint of image quality improvement in the recorded material obtained, in addition to the aforementioned points, it has been required that the color tone of the ink itself and permeability into an image-receiving paper are improved, and suppression of bronze generation of printed matters is improved.